This invention relates to an adjustable leg for supporting a table top whereby the height of the table top can be raised or lowered. The expression table top is intended to include any substantially horizontal surface which can support objects such as various sorts of table, television tables, desk tops and other surfaces for supporting for example typewriters and computer terminals.
Tables and desks particular for use with computer terminals and other equipment which includes keyboards or other devices which require close attention and manual operation need to be adjusted acurately to the required height of the individual using the equipment. In view of the large increase in usage of of such equipment there has developed a particular demand for tables of this type with the need for a rapid and accurate adjustment of the height particularly of the table itself which may or may not carry associated equipment attached to the table.
Various prior arrangements have been proposed for adjustable table tops generally comprising a single leg which has a screw or rack which can be raised or lowered by operation of a suitable actuating mechanism.
For example U.S. Pat. No. 944,560 provides a height adjustment mechanism in the form of an extension portion carrying a rack which is raised and lowered relative to a leg by a pinion and a manually rotatable handle carried on the leg.
U.S. Pat. Nos. 1,783,661 and 3,030,073 provide an externally screw threaded extension portion with a pedestal on which is mounted a hand wheel which surrounds the screw threaded portion and can be manually turned to raise the screw threaded portion to raise the table top.
However these arrangements are complex and therefore expensive to manufacture and are visually unappealing. Furthermore in view of the large number of parts involved they tend to be somewhat unstable and prone to wear between the various parts whereby the desired smooth action and accurate control can be lost.